Emulsifiers find widespread utility in many areas. Especially prevalent in the food industry are derivatives of hexitol anhydrides, or anhydrohexitols. For example, the fatty acid derivative of anhydrohexitols commonyl are used in formulations of confectionary fats and margarines.
Hexitols are hexanehexols, that is, n-hexanes each of whose carbon atoms bears a hydroxyl group. Similarly, pentitols are pentanepentols and tetritols are butanetetrols. Hexitols, pentitols, and tetritols are members of the class of polyols. Hexitols are commonly derived from hydrogenation of hexoses, during which the carbonyl group is reduced to a hydroxyl group. A particularly common hexitol is sorbitol whose frequent incidence among hexitols of commerce may be attributed, at least in part, to its being derived from glucose, an abundant and cheap raw material of widespread occurrence.
Sorbitol and other hexitols may be converted to anhydrohexitols with acid. For example, when hexitol is heated with two molar hydrochloric acid at 100.degree. C. for 100 hours a nearly quantitative yield of anhydrohexitols is obtained. Barker, R., J. Org. Chem. 35 p. 461, 1970.
It is desirable to prepare anhydrohexitols by a process to obviate the need of removing large quantities of acid where their presence is objectionable, as e.g., in subsequent use of the product in foodstuffs. It is also highly desirable to have a process whereby a hexose may be converted to anhydrohexitols in a single step.